Dulce de Leche: Remove and discard labels from the two tins of condensed milk. Place the unopened tins into a large saucepan and pour in enough water to cover by 3 to 6cm. Bring water to a boil over high heat, then reduce heat to medium, cover and simmer for 3 hours.

Drain and allow tins to cool to room temperature before opening.

Milhojas: Cook the puff pastry sheets according to package directions and allow to cool to room temperature.

Pour the dulce de leche from one tin evenly over a sheet of puff pastry. Place a second sheet of puff pastry over the first, then pour on the remaining tin of dulce de leche. Top with the remaining puff pastry sheet, then cut into 12 triangles.

To Serve: Heat a grill pan over medium-high heat and oil with cooking spray, or preheat an outdoor grill for medium-high heat. Grill the pineapple rings until warm and nicely marked.

Serve each triangle on a dessert plate garnished with a grilled pineapple slice and a scoop of citrus sorbet.